Chillies are the dried ripe red fruits of the genus capsicum. The two well-known species are Capsicum annum L. and Capsicum frutenscens L. India is the largest producer and exporter of chillies. The estimated export of dry chillies from India was 75,000 MT tonnes valued Rs 25580 lakhs in 2001-02.
Pungency and color are the two main quality attributes in chillies. The red color of chillies is due to the presence of carotenoid pigments like capsanthin, (major pigment, 35%) capsorubin, zeaxanthin, violaxanthin, cryptoxanthin, β-carotene etc. These pigments are present in chillies mainly the esterified form, and to a small extent in non-esterified forms. The oleoresin of chillies is used in many processed foods like sausages, seafood, meat products etc. to impart a reddish taint and pungency. It is also used in chicken feed so that chicken meat and yolk will get an attractive reddish shade. As a food colorant pungency-free, high color content chilli oleoresins are desirable. Chilli oleoresins as commercially produced very in their pigment are of the contact with the color value ranging from about 30,000 to 1,00,000 units as, measured by the method prescribed by the Essential oil Association of America (EOA). The oleoresin color content is directly proportional to the pigment concentration the raw material used. But preparation of oleoresin with high color value is desirable. The present invention relates to a process to upgrade the color value of pungency-free commercial chilli oleoresin.
There are several patents on chilli/paprika color, relating to the following aspects: (i) Methods for alcohol or oil extraction, usually after saponification with alkali. (ii) Pigment production by interesterification. (iii) Methods for pigment stabilization or prevention of fading and, (iv). Preparation of formulations for food use. Other patents relating to paprika color are as follows: Method of preventing paprika color from fading production of paprika color involving the use of calcium hydroxide and solvent extraction, improvement of paprika color stability to oxygen and light by blending with carrot extract and browning reaction product of a saccharide and amino acid. There are no methods reported in patent literature for the preparation of colourant from oleoresin. In particular the process is to enrich the color of pungency-free chilli and paprika oleoresin.
Reference may be made to Japanese patent JP 61264061 (1986) wherein paprika extract is treated with caustic alkali in presence of acetone to produce a dyestuff. The drawbacks are the treatment hydrolyses the fatty acid esters of carotenoid pigments, thereby altering their natural structure.
The present patent deals with pigment enrichment of chilli and paprika extracts and this approach has not been reported in earlier patents. In this patent a method is provided for the enrichment of the color value of pungency-free chilli oleoresin from the normal values (ranging from 30,000 to 70,000 EOA color units), by a physical process i.e. without changing the molecular structure of the carotenoid fatty acid esters, naturally present in chilli.
In the spice extraction Industry, chilli oleoresin is produced by extraction of chilli powder with solvents such as acetone, ethylene dichloride and hexane followed by desolventisation to get a deep red colored, viscous material called the oleoresin. The oleoresin contains the constituents responsible for color namely carotenoids, the pungent constituents mainly capsaicin and dihydrocapsaicin, besides other soluble components such as fats and waxes. This preparation is further processed by the Industry to obtain two products namely (i) a color fraction free of pungency and (ii) a pungent fraction containing low levels of color. It is the first fraction (color fraction), that is useful as a colorant in foods and also for poultry feeds. The Industry aims at producing the chilli color with a high color value, but the color content gets restricted due to the natural carotenoid content in the chilli. The present patent addresses this problem and provides a method to produce a colorant of enhanced color content, which will be useful especially in colorant formulations for food use.
Further some existing patents as mentioned above address the problem of enrichment of color value in chilli oleoresin, by the method of saponification wherein the natural ester bond between the carotenoids (manly capsanthin and capsorubin) and the fatty acids gets cleaved by the action of alkali to release the pigment. It is known that the solubility property of this pigment is different. It becomes almost insoluble in fatty media, necessitating formulation using emulsifiers and diluents. Also there are restrictions on the use of this altered pigment. The present patent does not face this drawback.